1. Field of the Invention
The present invention relates to an ink liquid supply system in an ink jet system printer. The present invention relates, more particularly, to an ink liquid reservoir included in an ink jet system printer of the printer of the ink-on-demand type.
2. Description of the Prior Art
An ink jet system printer of the ink-on-demand type generally includes an ink liquid reservoir mounted on a carriage which supports a printer head. An ink cartridge is removably disposed on the ink liquid reservoir in order to maintain the amount of ink liquid at a desired level in the ink liquid reservoir. The printer head includes a nozzle portion which communicates with the ink liquid reservoir so that the ink liquid is supplied from the ink liquid reservoir to the nozzle portion by means of the capillarity.
The ink reservoir is provided with an opening formed in the ceiling wall thereof so as to ensure stable ink liquid supply from the ink liquid reservoir to the nozzle portion. In the conventional system, the opening is a small opening so as to minimize the evaporation of the ink liquid through the opening.
However, there was a possibility that the small opening is blocked by the ink liquid when the ink cartridge is secured to the ink liquid reservoir because the pressure is increased in the ink liquid reservoir when the ink cartridge is secured to the ink liquid reservoir. Moreover, there was a possibility that the small opening is blocked by the ink liquid dropped from the ink cartridge when the ink cartridge is demounted from the ink liquid reservoir. The blocking of the small opening precludes an accurate operation of the ink jet system printer.